Margaret H. Chaffey, MD #{149} Jeffrey S. Klein, Paul Blanc, MD, MSPH #{149} Jeffrey A. Golden,

MD MD

#{149} Gordon

Gamsu,

MD

Radiographic Distribution of Psieumocystis carisali Pneumonia in Patients with AIDS Treated with Prophylactic Inhaled Pentamidine’ The radiographic distribution of Pneumocystis carinii pneumonia was studied in 64 consecutive patients with acquired immunodeficiency syndrome to determine the demographic and clinical factors that might be associated with predominance of the disease in the upper zones of the lungs. Twentythree patients were receiving monthly prophylaxis with 300 mg of aerosolized pentamidine by means of inhalation; the other 41 were not receiving pentamidine and served as a control group. Parenchyma! abnormalities were present in 63 of 64 patients. Pleural effusion and cystic lung lesions were uncommon and did not differ between the two groups. Patients receiving aerosolized pentamidine were more likely than control patients to have disease isolated or predominant in the upper lobes (odds ratio = 3.9, confidence interval = 1.1-14.1). After the possible effects of confounding variables were taken into account, prophylaxis remained a significant risk factor. Age and a previous history of P carin#{252}pneumonia were not significant cofactors. The pattern of deposition or retention of the aerosolized pentamidine could be responsible for the finding of predominant P carinii pneumonia in the upper lobes of the lungs.

P

CARINJI is the most common cause of pneumonia in patients with acquired immunodeficiency syndrome (AIDS). Monthly administration of inhaled, aerosolNEUMOCYSTIS

1989).

Several

gested

that

that

abnormalities inhaled pentamidine

I

From

1990; 175:715-719

the

Departments

of Radiology

(M.H.C., J.S.K., CC.) and Medicine (PB., J.A.C.), University of California, San Francisco, School of Medicine, San Francisco, CA 94143. From the 1989 RSNA annual meeting. Received November 16, 1989; revision requested December 21; revision received February 9; accepted February 26. Address reprint requests to CC. RSNA, 1990

group

whether

implicated pneumonia lungs.

in those with

and

other

to deter-

factors

could

in the distribution in the upper lobes

AND

study

population

patients with nia who were nod. Sixty-two or

bisexual

AIDS

of this of the

were

two

married

to men

positive

with

logic

patients

ranged

of AIDS

on were

during

virus

in age

from

had

the

a previous

diagnosed

diag-

as hayof P carinii

episode

evaluation

sputum medical

of spontaneous

specimens

stained

date

were

of initiation therapy. Exclud-

patients

of each

whose

pathologic mipreexisting thoprevious P carinii

22

all

but one patient showed clinical improvement with therapy, consistent with the diagnosis of uncomplicated P carinii pneumonia. up

Most

patients

radiography

underwent

that

lution

of the

tients

had

follow-

helped

confirm

pneumonia.

a diagnosis

None of or

reso-

of the

were

pa-

treated

for concomitant infection or malignancy. We did not study patients in whom P canflu was found only from bronchoalveolar lavage fluid or tissue specimens. Of 27 patients with a history of P caninii 17 were

receiving

prophylac-

10 were had three

the

most

recent

not. Twenone episode had two epiand time

one inter-

previous

epi-

monthly

doses

of 300

mg

of aerosolized

pentamidine administered in 4 mL sterile water, by means of nebulization with an Ultravent nebulizer (Mallin-

position around

and

for about 20 minutes. of prophylaxis (the

initiation and the months

treatment

breathed

functional

of pentamidine episode under ± 5.0 (median,

pneumoin the

at tidal

residual The interval

of

patients weekly immedi-

P caninii

before developing All patients received

sitting

9.6

vol-

capacity

mean duration between the

prophylaxis study) was 8.3 7.0 months; range,

or in-

with

silver. records

epi-

pneumonia), or in whom endobronchial Kaposi sarcoma was demonstrated by means of previous fiberoptic bronchoscopy. Review of the charts revealed that

ume

39 years ± 7.1 [stanmedian, 39 years).

either

methenamine The

previous

aerosolized

sputum yielded additional cnoonganisms, who had racic disease (except for

ately nia.

findings

pneumonia being studied. In all patients, P carinii was detected by means of cytoduced

study

factors

P carinii

cknodt, St Louis). One of these had received two consecutive doses of 300 mg of pentamidine

of in-

were

immunodeficiency

patients

AIDS

homosexual

a history

and

with

human

The

were had

abuse),

to 67 years (mean, dard deviation];

ing

the

risk

sode and the episode under study was months ± 4.7 (range, 1.5-21.0 months). Twenty-three patients were receiving

consisted of 64 P carinii pneumoduring a 13-month pe-

(one

and

the

nosis

ed from

sex,

of receiving

and the of prophylactic

val between

METHODS

patients

drug who

All

pentamidine, and dose

age,

of previous date of the

tic pentamidine, and ty-two of these patients of P caninii pneumonia,

and

seen

men

hemophilia for

history

pneumonia,

be

Patients The

for

history the

sodes, one had three episodes, had four episodes. The mean

PATIENTS

(HIV). Radiology

case

recurrent

in a control

mine

women of

sodes,

reports have sugP carinii pneumonia is distributed in the upper lobes of the lungs in patients receiving pentamidine by means of inhalation (1-3). This distribution of P carmu pneumonia was, however, described before the advent of prophylactic inhaled pentamidine in aerosol form (4). We therefore studied 64 patients with AIDS and P carinii pneumonia to compare the frequency of

radiographic receiving

reviewed

for AIDS, pneumonia,

ized pentamidine has reduced the incidence of P carinii pneumonia to about 20% in 12 months (Golden JA, Conte JE Jn; oral communication;

travenous Index terms: Acquired immunodeficiency syndrome (AIDS), 60.2518 #{149} Lung, effects drugs on, 60.64 #{149} Lung, infection, 60.2075

were

patient

Abbreviations: AIDS acquired ficiency syndrome, CI = confidence HIV = human immunodeficiency

immunodeinterval, virus.

715

Figure

1.

Posteroanterion

32-year-old man P caninii pneumonia phylactic inhaled

with

radiograph one

prior

who

of a

episode

of

was receiving

pentamidine.

pro-

There

is

dense airspace consolidation in the upper zones of both lungs and ground-glass opacities in the middle zones. Cytologic examination

of induced

P caninii. i.0-l9.0 months). dose of pentamidine

The

(range,

300-5,700

mg).

missed

a total

mean cumulative was 2,374 mg ± 48

Five patients

had

of 10 doses.

upper lobes more frequently, we evaluated on nadiographs the prevalence and severity of parenchymal disease in the upper zones compared with the middle and

lower Radiography Chest

radiognaphs

obtained

mediately preceding tion of P caninii were

terior

either

or following

analyzed. radiographs

and lateral

imisola-

Posteroanwere avail-

able in the majority of patients, and antenoposterion radiographs, In the others. These were reviewed, and a consensus

was

were

reached

aware

by

two

radiologists

of the diagnosis

pneumonia to clinical

corded

who

of P carinii

but were information.

otherwise Findings

on a scoresheet

designed

blinded were

for

re-

this

study. Each lung was divided into upper, middle, and lower zones. The patterns of parenchymal abnormalities were recorded as linear or reticular opacities, airspace consolidation, on ground-glass opacities for each of the six lung zones. The severity of abnormality in each zone was graded as 0 for absent, 1+ for mild, 2+ for moderate, on 3+ for severe. The presence of pleural effusions and hilar on mediastinal lymphadenopathy was noted, as was the presence of cystic lesions in the lung. Prior radiographs were used for comparison when there was a question of mild abnormality. Disease dominant in the up-

per zones ease

of the lungs

in one

one grade

on both

was defined

upper

of severity

any other zone; disease pen zones of the lungs renchymal abnormalities or both upper zones.

zones

more

as disof at least

than

that in

isolated to the upwas defined as palimited to one

Logistic

lung

the

develop

prophylactic

velop 716

dominant #{149} Radiology

hypothesis

pneumonia aerosolized

on isolated

that

patients

while pentamidine

disease

mality

being

isolated

de-

revealed

within

cysts

represent

from

the

previous

pneumonia.

not

was

used

to

of pneumonia in the upper

disease

of the

in

present

(any,

pneumonia

those

with

posure

upper

dominant,

of the

or

upper

a particular

risk

to prophylactic

tamidine)

zones)

factor

(ex-

aerosolized

divided

by

the

pen-

odds

of the

ab-

Figure

2. Frontal radiograph of a 51-yearpatient who had two prior episodes of P caninhi pneumonia and was receiving prophylactic inhaled pentamidine. Biapical air-

normality in patients lacking the risk facton. The confidence intervals (CIs) around the odds ratio describe the risk estimate

old

in

space

terms

of a chance

CI that excludes cally

tially

regression

to include

variables

continuous gistic

variable)

tiple

and

pneumonia.

regression

lowed

recurrent

consolidation P caninii

the

with

history

We employed

approach

a lo-

because

us to simultaneously factors

(as a

previous

it al-

analyze

a dichotomous

muloutcome

four middle individually

and lower zones in the patients

pentamidine Finally,

versus

the middle and with radiographic regions

numbers

in

subgroup.

a logistic

regression

who were not, severity scones = 1, maximum

each

of months variable)

in the

upper

receiving

analysis, (continuity

of any

We

analysis

also

zones

adjusted)

disease

(as a of pneu-

among

pentamidine.

we also

used

to examine

of treatment on the risk

used

the

pa-

For

supple-

the

x2 sta-

to evaluate

in each

of the

was

tients

the

ing

Wilcoxon

of the receiving

who

whether

or

less

lungs

were

not.

disease

lower zones involvement

more

receiving

the

those

to evaluate

or absence of disease) the problems of small

tistic

to represent

poten-

of age

(ie, the presence while we avoided

presence

was found pneumonia.

of .05. The by using multiple

repeated

confounding

of P caninii

A 95%

of 1.0 is statisti-

at a P value

were

logistic

observation.

the ratio

significant

analyses

mental

of the

analysis

relative odds more frequently (any

consolidations

P caninii

specimens

lucencies

receiving

and those prophylaxis.

regression

the

zones

tients

receiving

patients

sputum

rounded

zones, regardless of the status of the middle and lower zones), disease dominant in the upper zones (as defined previously), or disease isolated to the upper zones in the patients receiving pentamidine yensus those who were not. The relative odds or the odds ratio is an estimate of risk and may be defined as the odds of an abnor-

monia To test

among

prophylaxis pentamidine

estimate developing

the effects continuous

Analysis who

zones

pentamidine receiving

The

among those in these

severe

pentamidine

of

in

the

versus

pathose

we compared the summed (minimum possible score possible score 12) by usrank

sum

test.

We

ex-

cluded from this analysis patients without any disease of the middle or lower zones (ie, scone 0). In all analyses, a standard computerized statistical package was used.

June

1990

Table

2 of Radiographic Pentamidine

Distribution

Prophylactic

zones in the upperzonest in the upper zones onlyt

Note.-Percentages * Mean age, 40.0 t Mean

age,

Not Receiving Pentamidine (n = 41)t

20 (87)

In the upper

Dominantdistnibution Distribution

and Not Receiving y/x-1/2

Receiving Pentamidine (n 23)*

Opacities AEty distribution

Receiving

in Patients

Opacities

8...

30 (73) 8(20) 3 (7)

13 (57) 9 (39)

8,

#{149}

Total

a

50 21 12

in parentheses. years 7.5. None were female. years ± 8.5. Two (5%)were female.

37.8

I p < .006. § P < .005.

0

1

2

3

4

Total

midde

5

6

7

lower

+

8

Figure

Table

3

Risk of P carinil Pneumonia Patients Receiving Pentamidine Analysis iii 64 Patients

Involvement Prophylaxis,

in Upper

Analysis

.

with

Odds

Any disease in upper zones (a Univaniate Multiplet Disease dominant in upper zones Univari#{225}te Multiplet Disease in upper zones only (n

Odds

t Significant

t Multiple S Defined any middle I Defined

ratio

is a risk

with

that

estimate

defined

in

Regression 95% CIt

summed and lower of identity of disease the middle

lower

patients

zones

to that

(n

0.6-10.2 0.6-16.0

in the upper

5.4 3.9

1.7-17.0 1.1-14.1

8.1 5.9

2.5-27.0

the line (ratio predominantly

as the odds

of an abnormality

Fifty

RESULTS The radiographic findings in the 64 patients in this study are shown in Table 1. Sixty-three of the 64 patients had abnormal findings on radiographs obtained at the time that P carinii pneumonia was diagnosed. The 63 patients had the following pa(n

patterns: = 42),

(n

=

(n

=

parenchymal

ground-glass linear on reticular

29), and airspace 16). A combination

patterns

was

conof

seen

in 20

patients: ground-glass and reticular opacities (n = 10), ground-glass opacities and airspace consolidation (n 6), and reticular opacities and airspace consolidation (n 4). All three abnormalities were present in four patients. Six patients (9%) had small pleural effusions in the left lung (n 4), in the right lung (n 1), and in both lungs (n 1). Hilar or mediastinal

lymph

node

enlargement

and

lung cysts were each seen in five patients (8%). Two patients presented with a pneumothorax (3%), one of whom had cystic changes on the mitial radiograph. Volume

175

Number

#{149}

3

zones

12

was in the

than upper

scores rep. in the and

not re-

(0) had the line (ralower zones

less than middle

1:2, and

patients receiving (#{149}) had scones

of more in the

11

penabove

1:2, or disease zones).

9)11 1.1-31.2 in patients

with

the risk

grade

more

factor

than

in

ing their first episode of P carinii pneumonia and one had recurrent disease. There was no demonstrable relationship between the presence of adenopathy and the pattern, distribution, or severity of parenchymal opacities.

Focal

opacities opacities solidation

Most

disease

lower zones). Most tamidine prophylaxis

i3)t

in patients lacking that risk factor. at P < .05, excludinga ratio of 1.0. logistic mode! included age and history of previous P carinii pneumonia. as severity of disease in upper zone of one or both lungs of at least one or lower zone. as disease limited to one or both upper zones.

renchymal

(1:2 ratio).

or predominant

2.4 3.2

10

3. Scatter plot of the for the upper versus middle zones of the lungs. The line resents an even distribution upper zones compared with

ceiving pentamidine prophylaxis scores that were about on below tio of disease in the middle and

20)

Multiplet C

Lungs

Logistic

Ratio*

Univaniate

compared

of the

Zones

Estimated

9

zone score

of the

64 patients

(78%)

had

radiographic opacities of a grade of at least 1 + in the upper lung zones due to P carinii pneumonia. Twenty-one patients (33%) had opacities involving

the

vene

upper

zones

involvement

middle

only

than

or lower

on more

in either

zones

se-

the

(dominant

disease in the upper zones) (Fig 1), while 12 (19%) had opacities limited to one or both upper zones (isolated disease of the upper zones) (Fig 2). Because all but two of the 64 patients studied were homosexual or bisexual and all but two were male, the relationship between risk factors for AIDS or gender and radiographic patterns of disease could not be tested.

The

six patients

with

sion showed no pattern tions. Five had previous carinii pneumonia, and

ceiving

prophylactic

tamidine. Of on mediastinal

receiving and both

pleural of associaepisodes

four were aerosolized

five patients adenopathy,

pentamidine had previously

pneumonia.

Of

receiving

prophylaxis,

the

effuof P

repen-

with hilan two were

prophylaxis, had P carinii

three

patients

two

were

not

hay-

lung

cysts

were

patients, three tory of previous

of whom infection

flu. Of

patients

the

two

P carinii pneumonia, ing prophylactic time of recurrence

five

patients

with

There cystic

diographic

in five

gave no hiswith P can-

with

previous

one was neceivpentamidine at the (Fig 1). One of the

cysts

with a spontaneous and had moderately renchymal opacities

zones. tween

seen

presented

pneumothonax severe (2+) in all lung

was no relationship changes and other

pa-

bera-

abnormalities.

Two

patients

had

a pneumothorax

at the time of presentation; both previously had P caninii pneumonia and were receiving prophylactic

aerosolized

pentamidine.

One

had

had

diffuse parenchymal opacities and cystic changes in the upper zones, and the other had mild (1+) opacities limited to the upper zones bilaterally.

Twenty of the 23 (87%) ceiving pentamidine had in the

upper

zones

on

patients pneumonia

me-

nadiographs;

30 of 41 (73%) patients not receiving pentamidine had disease in the upper zones of the lungs (Table 2). Isolated on more severe opacities in the upper zones than in either the mid-

Radiology

#{149} 717

dle or lower zones, however, were seen in 13 of 23 (57%) of the patients receiving pentamidine but in only eight of 41 (20%) not receiving pentamidine (Fig 1). Similarly, isolated pneumonia in the upper zones of the

(78%) who had previous P caninii pneumonia and in a similar proportion of patients without a prior episode (29 of 37). Thirteen of the 27 patients (48%) with previous P caninii pneumonia had dominant or isolated

disseminated P caninii infection in such patients (12,13). These findings suggest that with widespread prophylaxis with aerosolized pentamidine, we may begin to see an in-

creased

frequency

lungs

was

disease

P caninii

infection

tients

(39%)

but

observed

in only

receiving three

ceiving The

the drug relationship

status

to any,

pneumonia and without ing effects

in nine

of 23 pa-

pentamidine

of 41 (7%)

not

re-

(Fig 2). of prophylaxis

dominant,

or

isolated

of the upper zones, with the possible confoundof age and previous P can-

nii pneumonia,

are

presented

in Ta-

ble 3. The odds ratio derived from the logistic regression is the ratio of the odds of an abnormality being present in the group of patients receiving pentamidine, divided by the odds of the abnormality being present in the group not receiving pentamidine.

The

odds

of dominant

pneumonia in the upper zones among those receiving pentamidine was 5.4 times that of those not receiving pentamidine (univariate logistic regression analysis), although somewhat less (3.9) when the effects of patient age and prior P caninii pneumonia were considered (multivariate logistic regression analysis). Analysis by means of logistic regression of the 23 patients receiving prophylactic

pentamidine revealed no statistically significant relationship between the duration of prophylaxis before the development of P caninii pneumonia and the development of dominant disease in the upper zones. Patients not receiving prophylaxis with aerosolized pentamidine were significantly more likely to demonstrate disease on radiographs in each of the four middle on lower lung zones than patients receiving prophylaxis (P < .05 for each zone). Comparison of disease severity and extent in the middle and lower lung zones among those with any disease in this

region

(n

51)

(scored

as a

sum of the severity in each of the four regions, with summed scores ranging from 1 to 12) showed that patients not receiving pentamidine (n

38)

had

a higher

score

volvement in these regions those receiving pentamidine This difference not achieve,

Radiology

#{149}

eight of 37 patients previous P caninii finding. Isolated

zones,

but

only

(22%) without pneumonia had this upper zone opaci-

ties occurred in nine of 27 patients (33%) with prior P caninii pneumonia, compared with just three of 37 (8%) without prior disease. The odds ratio for dominant upper zone pneumonia

was

3.4 (95%

isolated 23.6).

gether

CI

disease, However,

with

1.1-10.0),

=

and

5.7 (95% CI when analyzed

age

and

for 1.4to-

prophylaxis

in

the multivaniate logistic regression, prior P caninii pneumonia was no longer significantly related to dominant or isolated pneumonia in the upper zones (odds ratio for dominant pneumonia in the upper zones 1.8, CI = 0.5-6.7; odds ratio for isolated

disease =

in the

upper

zones

2.7, CI

0.5-14.2).

DISCUSSION P caninii pneumonia 80% of patients with

occurs in 60%AIDS (4) and is

the major identifiable cause of death in 25% (5). Systemic pentamidine, a major therapeutic modality against the disease, causes significant morbidity in many patients, including

azotemia

(65%),

hypotension (24%), nausea

leukopenia

(27%),

(47%),

severe

anemia

and vomiting (24%), and hypoglycemia (21%) (6). Inhaled pentamidine, currently being studied for treatment and used for prophylaxis, only rarely elicits side effects or reactions, patients with previous systemic pentamidine (5,7-1 1).

significant even among reactions to therapy

The efficacy of pentamidmne inhaled monthly as prophylaxis against P caninii pneumonia has been well documented. In a series of 103 patients

receiving

pentamidine can caninii pneumonia

than 13). did by

means of the Wilcoxon rank sum test (P = .12). The disease severity score for the upper zones compared with that of the middle and lower zones in each patient is shown in Figure 3. Any involvement in the upper zones was seen in 21 of 27 patients 718

upper

this

therapy

who

were followed up for 6.4 months, Golden et al (8) found that inhaled

of in-

(n approached, but statistical significance

in the

reduce

the

rate

delay

relapse

of P

by 6 months and of relapse by 50%. Ad-

ditionally, inhaled pentamidine prophylaxis diminished the mortality due to P caninii pneumonia to 9%,

compared with 20% among those not receiving prophylaxis. Although aerosolized pentamidine is clearly effective in reducing the frequency of recurrent P caninii pneumonia, two recent articles described systemically

of extrapulmonary in patients

with

AIDS. Because

inhaled pentamidine appears to reduce the mortality associated with P caninii pneumonia, it is important to analyze the factors contributing to failure of the therapy. Abd et al (1), Scannell (2), and Conces et al (3) have reported single cases of P caninii pneumonia occurring exclusively in upper lung zones in patients receiving inhaled pentamidine prophylaxis. These authors have speculated about the explanation for this relatively uncommon distribution of disease, but, to our knowledge, no study has confirmed the relationship between monthly pentamidine prophylaxis and P canflu pneumonia in the upper zones. This study is a partially blinded retrospective analysis of chest radiographic findings in P caninii pneumonia. A common limitation of such a study is the lack of matching of age, sex, or risk factors between two patient groups. These are homogeneous factors in the patients with AIDS or with positive findings for HIV in our population. Thus, more legitimate comparisons can be made between the two patient groups in this study. Diagnoses were made in all patients on the basis of findings at cytologic evaluation of sputum. Any influence that this element might have on our findings, however, is uniform in the patients receiving and not receiving prophylaxis. Additionally, more severe disease may allow cleanen distinction of radiographic abnonmalities. At present, we are studying the distribution of P caninii pneumonia in a growing number of patients with AIDS (now more than 25 patients) whose conditions were diagnosed by means of bronchoalveolar lavage during the same period to determine whether this distinct group of patients has similar patterns of disease dominant in or confined to the upper lobes. The radiographic patterns of P canflu pneumonia exhibited in the patients in this study are similar to those seen in earlier large series of patients with chest radiographic findings of P caninii pneumonia (14). A ground-glass on reticular pattern of disease is more common than airspace consolidation. Other features, including cystic changes, pleural ef-

June

1990

enetniaminepentaacetic

fusions, hilan enlargement, and pneumothoraces, are all uncommon. Our data confirm the association

between

inhaled

pentamidine

phylaxis and dominant or isolated distribution of P caninii pneumonia the upper lobes by demonstrating statistically significant increased of such abnormalities. Furthermore,

tamidine aerosol

proin a risk

this relationship is independent of patient age and the duration of prophylactic pentamidine therapy. Pnevious P caninii pneumonia may independently predispose the upper zones of the lungs to recurrent pneumonia, perhaps because inflammation and scarring from previous infection have altered local ventilation and perfusion, factors influencing deposition and retention of inhaled pentamidine. Many patients receiving inhaled pentamidine prophylaxis have had prior P caninii pneumonia (including those described by Scannell [2] and Conces et al [3]). Abd et al (1) do not give a full medical history of the patient described in their case report, and a history of the disease may be a confounding variable. However, our data do not suggest that prior P caninii pneumonia accounts for the relationship of prophylaxis to upper lung disease. In-

deed,

when

analyzed

together

with

age and prophylaxis, prior P caninii pneumonia was not a statistically significant risk factor for disease in the upper lobes of the lungs, while pentamidine prophylaxis remained a significant risk factor. The predisposition to isolated or dominant P caninii pneumonia in the upper lobes among patients neceiving prophylaxis and the relative protective effect of prophylaxis on the middle and lower lung zones remain unclear. Scannell (2) and Conces et al (3) have speculated, and Abd et al (1) have investigated (by measuring megional distribution in the lung of a mixture of technetium-99m diethyl-

175

#{149} Number

3

acid

and

by means the possibility

pen-

dine prophylaxis, we must determine the variables we can manipulate in treating patients with AIDS and patients with positive findings for HIV. Because a significant percentage of patients who “break through” pentamidine prophylaxis develop dominant on exclusive P caninii pneumonia in the upper lobes of the lungs and because it has been clearly established that prophylaxis reduces recurrence rates to approximately 20% in 1 year, any method that increases deposition or retention of the aerosolized pentamidine in the upper lobes should further reduce this rate. We are currently conducting studies with radiolabeled compounds to determine the influence of patient position, breathing pattern, and nebulizem devices on deposition and netention of inhaled pentamidine. The association of prophylaxis with disease in the upper lobes of the lungs should not be interpreted to suggest that this involves a “tradeoff” with distribution of P caninii in other zones. Because entry into our study required that a patient have a diagnosis of P caninii pneumonia, we cannot address differences in the incidence or prevalence of P caninii pneumonia between groups receiving and not receiving prophylaxis. Rather, as prophylaxis with aerosolized pentamidine becomes the standard of practice, we might expect to see a change in the pattern of P caninii pneumonia, with dominant disease in the upper lung zones becoming typical

radiographic

finding.

References 1.

of

that pneumonia in the upper lobes is due to diminished deposition of aerosolized pentamidine in those aneas. Another factor could be more rapid removal of inhaled pentamidine from the upper zones compared with that of the middle and lower zones. To optimize inhaled pentami-

the

Volume

administered to a patient)

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

Abd A, Nierman DM, Ilowite B, Pierson RN Jr. Bee AL Jr. Bilateral upper lobe Pneumocystis carinii pneumonia in a patient receiving inhaled pentamidine prophylaxis. Chest 1988; 94:329-331. Scannell KA. Atypical presentation of Pneumocystis carinii pneumonia in a patient receiving inhalation pentamidine. Am Med 1988; 85:881-884. Conces DJ Jr. Kraft JL, Vix UA, Tarver RD. Apical Pneumocystis carinii pneumonia after inhaled pentamidine prophylaxis. AJR 1989; 152:1193-1194. Milligan SA, Stulbarg MS. Camsu C, Golden JA. Pneumocysfis carinii pneumonia radiographically simulating tuberculosis. Am Rev Respir Dis 1985; 132:1124-1126. Kovacs JA, Masur H. Pneumocystis carinii pneumonia: therapy and prophylaxis. Infect Dis 1988; 158:254-259. Sattler FR, Cowan R, Nielson DM, Ruskin J. Tnimethopnim-sulfamethoxazole compared with pentamidine for treatment of Pneumocystis carinil pneumonia in the acquired immunodeficiency syndrome: a prospective non-crossover study. Ann Intern Med 1988; 109:280-287. Centers for Disease Control. Update: acquired immunodeficiency syndrome (AIDS)-United States. MMWR 1986; 35:17-21. Golden JA, Chernoff D, Hol!ander H, Feigal D, Conte JE. Prevention of Pneumocystis carinii pneumonia by inhaled pentamidine. Lancet 1989; 1:654-657. Havlichek D. Aerosolized pentamidine therapy (letter). Ann Intern Med 1988; 109:167-168. Montgomery AB, Debs RJ, Luce JM, et a!. Aerosolized pentamidine as sole therapy for Pneumocystis carinhi pneumonia in patients with acquired immunodeficiency syndrome. Lancet 1987; 2:480-483. Conte JE Jr. Hollander H, Golden JA. Inhaled or reduced-dose intravenous pentamidine for Pneumocystis caninii pneumonia: a pilot study. Ann Intern Med 1987; 107:495-498. Davey RI Jr. Margolis D, Kleiner D, Deyton L, Travis W. Digital necrosis and disseminated Pneumocystis carinii infection after aerosolized pentamidine prophylaxis. Ann Intern Med 1989; 111:681-682. Radin DR. Baker EL, Klatt EC, et a!. Visceral and nodal calcification in patients with AIDS-related Pneumocystis carinii infection. AJR 1990; 154:27-31. DeLorenzo U, Huang CT, Maguire CP, Stone DJ. Roentgenographic patterns of Pneumocystis caninii pneumonia in 104 patients

with

AIDS.

Chest

1987;

91:323-327.

U

Radiology

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